This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | -2 |
| 3 | 1 |
| 4 | -6 |
| 5 | 12 |
| 6 | 1 |
| 7 | -12 |
| 8 | 60 |
| 9 | -120 |
| 10 | 1 |
| 11 | -20 |
| 12 | 180 |
| 13 | -840 |
| 14 | 1680 |
| 15 | 1 |
| 16 | -30 |
| 17 | 420 |
| 18 | -3360 |
| 19 | 15120 |
| 20 | -30240 |
| 21 | 1 |
| 22 | -42 |
| 23 | 840 |
| 24 | -10080 |
| 25 | 75600 |
| 26 | -332640 |
| 27 | 665280 |
| 28 | 1 |
| 29 | -56 |
| 30 | 1512 |
| 31 | -25200 |
| 32 | 277200 |
| 33 | -1995840 |
| 34 | 8648640 |
| 35 | -17297280 |
| 36 | 1 |
| 37 | -72 |
| 38 | 2520 |
| 39 | -55440 |
| 40 | 831600 |
| 41 | -8648640 |
| 42 | 60540480 |
| 43 | -259459200 |
| 44 | 518918400 |
| 45 | 1 |
| 46 | -90 |
| 47 | 3960 |
| 48 | -110880 |
| 49 | 2162160 |
| 50 | -30270240 |
| 51 | 302702400 |
| 52 | -2075673600 |
| 53 | 8821612800 |
| 54 | -17643225600 |
| 55 | 1 |
| 56 | -110 |
| 57 | 5940 |
| 58 | -205920 |
| 59 | 5045040 |
| 60 | -90810720 |
| 61 | 1210809600 |
| 62 | -11762150400 |
| 63 | 79394515200 |
| 64 | -335221286400 |
| 65 | 670442572800 |